Long-term exposure to outdoor air pollution has been associated with increased cardiopulmonary mortality in developed countries, but there exist no prospective evidence in developing countries. It is unknown whether the findings from low air pollution exposure settings in developed countries apply to developing countries, where characteristics of outdoor air pollution and socio-demographic status of local residents are different. The overall objective of this proposed project is to determine the effects of long-term exposure to outdoor air pollution on mortality in a nationally representative cohort of 79,984 middle-aged men and women in 52 districts of China. We will address the following specific aims: 1. To obtain the annual average air pollution exposure (TSP, SO2, and NOx) between 1991 and 2000 in each district. 2. To determine the effects of long-term exposure to outdoor air pollution on total and cause-specific mortality. 3. To examine potential modifiers of the association between long-term exposure to air pollution and mortality. Baseline data on the participants'demographic characteristics, medical history, lifestyle-related risk factors, blood pressure, and body weight were obtained in 1991 with the use of a standard protocol. The follow-up evaluation was conducted in 1999 and 2000. Annual average air pollution exposure between 1991 and 2000 will be estimated by linking fixed-site monitoring data with resident zip code. The association of air pollution with mortality will be examined using proportional hazards regression models, with adjustment for a wide range of individual risk factors. Both total and cause-specific mortality will be assessed. We will fit both single-pollutant and multi-pollutant models to assess the stability of pollutants'effects, and will present the nonparametric smoothed exposure-response relationship between mortality and pollutant concentrations. Stratified analyses by sex, smoking status, obesity, and education will be conducted to examine potential modifiers of the association between air pollution and mortality. The proposed study will generate the first prospective evidence of the association between air pollution and mortality in developing countries. The results from this study will contribute to very limited data in the scientific literature on long-term effects of air pollution for high exposure settings typical in developing countries. The study matches the NIH's current strategy of global environmental health, and will fill key knowledge gap of air pollution health effects in China. PUBLIC HEALTH RELEVANCE: Levels of outdoor air pollution in China are among the highest in the world;however, there exists no prospective data of the long-term effects of air pollution in China. This proposed project will build on a well-characterized nationally representative cohort in China and assess the relationship between long-term exposure to air pollution and mortality. The findings of this study will fill key knowledge gap of air pollution health effects in China.